我是 iOS 开发的新手，但最近参加了广泛的速成课程（BNR 指导 iOS 编程）。我正在以模态方式向应用程序添加视图。我目前没有 View Controller，所以我的 AppDelegate 的application:didFinishLaunchingWithOptions方法如下所示：
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
MyUIView *map = [[MapSurface alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
//this one does not work: MyUIView *map = [[MapSurface alloc] initWithFrame:CGRectMake(0, 0, 256, 256)];
[map setBackgroundColor:[UIColor grayColor]];
[[self window] addSubview:map];
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}
视图加载后，我调用添加子视图，但无法使用CGRectMake. 它不会出现在屏幕上。我发现唯一有用的是使用屏幕尺寸，但这不是我想要的。这是添加此子视图的代码：
UIImage *image = [[UIImage alloc] initWithCGImage:img];//img is a CGImageRef
UIImageView *view = [[UIImageView alloc] initWithImage:image];
CGRect b = CGRectMake(0, 0, 256, 256);
//[view setFrame:b];//nothing shows on screen
//[view setBounds:b];//nothing shows on screen
//[view setBounds:[[UIScreen mainScreen] bounds]];//shows the tan area in the graphic below
[view setFrame:[[UIScreen mainScreen] bounds]];//fills the screen
[map addSubView:view];
CGImageRelease(img);
